The present invention relates generally to electrical control and monitoring systems, such as systems used in industrial and other electrical power applications. More particularly, the invention relates to a technique for mounting and interfacing of power control devices, particularly well-suited to use at or near a driven or powered load.
A wide range of applications exist for applying and controlling electrical power in industrial, marine, agricultural, commercial and other settings. The many such applications, a powered load, such as an electric motor, is provided with single or three-phase electrical power. The power originates in the power grid, and is channeled to the application through various distribution circuits and, ultimately, protective circuitry and switch gear at or near the load. In industrial applications, for example, motors have traditionally been controlled through a range of devices that are mounted in and interlinked in large electrical enclosures or cabinets, typically called motor control centers (MCC).
A growing alternative to MCCs involves the separation of power distribution, control and monitoring circuitry to locate individual and distributed systems near the actual loads that they control. For example, an industrial setting, many motors and other actuators may be controlled for a particular machine process. On-machine systems are being designed to control one or a handful of such motors via distributed systems located near the individual motors and mounted to a machine frame. Such applications, while potentially reducing costs and improving local control, pose substantial difficulties. For example, the on-machine environments are often subjected to considerable vibration and environments around the machine systems are potentially less controlled than are those in a central enclosure. However, the benefits of local control, reduced wiring costs, and decentralization of functionality help to drive such solutions.
Existing on-machine control and monitoring systems are generally packaged as a pre-designed unit. That is, all necessary drives, drive circuitry, protective circuitry, switch gear and the like are included in a packaged enclosure. While such solutions are workable, further improvements are believed useful. For example, there is a need in the art for systems that will facilitate a modular approach to selection and interfacing of protective circuitry, drive circuitry, switchgear, and the like. Similarly, there is a need for a system that will permit environmentally-controlled electrical interfacing in a package that can be expanded or contracted to meet the local power distribution and control needs.